Description Logic (DL) [1]} is a state of the art formalism that allows to represent and reason on symbolically structured knowledge.
DL lies within the decidable fragment of languages that are based on first-order logic, and it has been standardised by the World Wide Web Consortium (W3C) as OWL-DL.
OWL [2]} allows to design ontologies, which are semantic corpora containing knowledge encoded as logically-defined symbols meant at being readable by humans and machines.
An ontology is defined within a context, i.e., a consistent corpus of knowledge representing a domain of interest [3]}.
Within a context, a reasoner can evaluate the consistency of knowledge by performing subsumption, instance-checking and inference based on well-defined rules [4]}.
Several reasoners have been proposed, some of which are discussed in [5]}.
Deterministic DL reasoners (e.g., Pellet [6]}) do not represent uncertainties, whereas fuzzy [7]} or probabilistic [8]} OWL reasoners do.
DL reasoning is computationally expensive, and this limits its online usage, especially when the context is information-rich.
In particular, the computation scales exponentially with the amount of knowledge encoded in an ontology [1]}.
